WASHINGTON -- Terrorists "found a second chance" to thrive in Iraq, the nation's prime minister said Thursday in asking for new U.S. aid to beat back a bloody insurgency that has been fueled by the neighboring Syrian civil war and the departure of American troops.

Iraqi Prime Minister Nouri al-Maliki told a packed auditorium at the U.S. Institute of Peace that he needs additional weapons, help with intelligence and other assistance, and claimed the world has a responsibility to help because terrorism is an international concern.

"If the situation in Iraq is not well treated, it will be disastrous for the whole world," said al-Maliki. "Terrorism does not know a single religion, or confession, or a single border. They carry their rotten ideas everywhere. They carry bad ideas instead of flowers. Al-Qaida is a dirty wind that wants to spread worldwide."

The new request comes nearly two years after al-Maliki's government refused to let U.S. forces remain in Iraq with legal immunity that the Obama administration insisted was necessary to protect troops. President Barack Obama had campaigned on ending the nearly nine-year war in Iraq and took the opportunity offered by the legal dispute to pull all troops out.

Nearly 4,500 U.S. troops were killed in Iraq between the 2003 invasion and the 2011 withdrawal.

Al-Maliki will meet today with Obama in what Baghdad hopes will be a fresh start in a complicated relationship marked by victories and frustrations.